View Compilation Error

0_0_25826014_18228.cpp: In function 'long long int solve(int, int)':
0_0_25826014_18228.cpp:13:16: error: 'pow2' was not declared in this scope
     int sum = (pow2[n] * factorial[n]) % mod;
                ^
0_0_25826014_18228.cpp:13:26: error: 'factorial' was not declared in this scope
     int sum = (pow2[n] * factorial[n]) % mod;
                          ^